Method of pouring ingots



Patented June 9, 1953 METHOD OF POURING INGOTS William F. Walter, Jr.,Greenoek, and William J.

Wysor, Bittsburgh, Pa., assignors .to' United States Steel Corporation,a corporation of New Jersey No Drawing. Application June 14, 1950,Serial No. 168,144

This invention relates to the pouring of ingots and to a novelcomposition for coating the interior of ingot molds prior to teemingmolten metal thereinto.

It has long been the practice to apply a coating to the interior ofingot molds to prevent the formation of scabs in the surfaces of theingots as a result of the splashing of liquid metal against the moldWalls during teeming. Tar is perhaps the material most widely used forthis purpose but it is objectionable because of the large volume ofsmoke it produces when the molten metal comes into contact with it, aswell as other reasons. We have invented a novel mold-coating compositionwhich is free from the objectionable characteristics of tar and othermaterials which have been used for the purpose, and possesses numerousadditional advantages.

In general terms, our improved method consists in coating the molds witha mixture of ground bituminous coal and a vegetable binder such asstarch, dextrin or cereal flour mixed with sufficient water to provide afluid wash which may be applied by a spray gun. We may employ anybituminous coal for the purpose of our invention but prefer ahigh-volatile coal having low ash and sulphur contents. The coal isground to the size of small granules but not too fine. The particlesshould be of such size that nearly all, say 95%, will pass through a40-mesh screen while not more than 50% will pass through a 200-meshscreen.

The binder may be starch, dextrin or the flour of a cereal grain, e. g;,wheat, rye or corn. Among the latter, corn is preferred. Whatever thebinder, it is obtained in pulverized form and thoroughly mixed with thedry coal. Water is then added to the dry ingredients .toform a paste andthis is then thinned with additional water to bring it to a state ofready fiowability. The ranges of the proportions ,of the severalingredients are given in the following table showing several examples,the last of which is the preferred practice.

Cereal flour for use in our mold coating is prepared by decorticatingthe kernels, freeing 1 Claim. (Cl. 22-189) 2 them from the germ,steaming them until about 40% of the starch is converted into sugar,then drying and grinding them to flour.

According to our invention, the mold coating may be applied either tocold or to warm ingot molds, preferably by means of a spray gun fed froma tank containing the mixture in a state of agitation by means ofcompressed air jets or otherwise. The coating is applied to the interiorsurfaces of the mold until they are uniformly and continuously coated.This requires about one and one-half pints of the coating for an averagesize steel-mill ingot mold which corresponds substantially to 270 squarefeet of mold surface 7 per gallon. With the described practice, an ingotmold can be properly coated in about six-seconds, producing a coatingwhich is ready for instantaneous use.

In addition to the economy and ease of application mentioned above, ourmold-coating composition has several other advantages. When properlyapplied, it repels splashes, sprays,

surges, etc., which strike the mold wall, causing them to fall back intothe ingot body rather than adhering to the mold wall to create surfaceimperfections. The coating remains on the mold wall throughout thetimeitis needed and does not burn off with a flash with the first splashof the metal in the mold. It burns just ahead of the rising steel andmaintains the reducing atmosphere throughout the ingot poursembling thatof toasted bread can be observed. I

We claim: Ina method of pouring steel ingots, the steps including makinga composition consisting essentially of granulated bituminous coal of asize such that will pass through a 40- mesh screen but not more than 50%will pass through a 200-mesh screen, flour ground from steamed cornkernels and water, in the proportions of about pounds of coal, about 10pounds of flour and about 20 gallons of water, coating the interiorwalls of an ingot mold with said composition and teeming liquid steelinto the mold, said coating having the property of remainingsubstantially unaffected above the level of the steel in the mold andburning ofl progressively just ahead of the steel surface as it rises,thereby affording a pronounced deoxiclizing action at said surface.

WILLIAM F. WALTER, JR. WILLIAM J. WYSOR.

Name Date Number Hartman Sept. 28 1902 Number I Name DateGernelle-Danloy Mar. 6, 1917 Allison May 9, 1950 Baker May 23, 1950FoREIGNrZiTENis Country Date Great Britain Sept. 2, 1931 OTHERREFERENCES 214-218, received in Scientific Library October

